/* ----------------------------------------------------------------------
 * Project:      CMSIS DSP Library
 * Title:        arm_sin_cos_q31.c
 * Description:  Cosine & Sine calculation for Q31 values
 *
 * $Date:        18. March 2019
 * $Revision:    V1.6.0
 *
 * Target Processor: Cortex-M cores
 * -------------------------------------------------------------------- */
/*
 * Copyright (C) 2010-2019 ARM Limited or its affiliates. All rights reserved.
 *
 * SPDX-License-Identifier: Apache-2.0
 *
 * Licensed under the Apache License, Version 2.0 (the License); you may
 * not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an AS IS BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include "arm_math.h"
#include "arm_common_tables.h"

/**
  @ingroup groupController
 */

/**
  @addtogroup SinCos
  @{
 */

/**
  @brief         Q31 sin_cos function.
  @param[in]     theta    scaled input value in degrees
  @param[out]    pSinVal  points to processed sine output
  @param[out]    pCosVal  points to processed cosine output
  @return        none

  The Q31 input value is in the range [-1 0.999999] and is mapped to a degree value in the range [-180 179].
 */

void arm_sin_cos_q31(
	q31_t theta,
	q31_t *pSinVal,
	q31_t *pCosVal)
{
	q31_t fract;                                     /* Temporary input, output variables */
	uint16_t indexS, indexC;                         /* Index variable */
	q31_t f1, f2, d1, d2;                            /* Two nearest output values */
	q31_t Dn, Df;
	q63_t temp;

	/* Calculate the nearest index */
	indexS = (uint32_t)theta >> CONTROLLER_Q31_SHIFT;
	indexC = (indexS + 128) & 0x1ff;

	/* Calculation of fractional value */
	fract = (theta - (indexS << CONTROLLER_Q31_SHIFT)) << 8;

	/* Read two nearest values of input value from the cos & sin tables */
	f1 =  sinTable_q31[indexC  ];
	f2 =  sinTable_q31[indexC + 1];
	d1 = -sinTable_q31[indexS  ];
	d2 = -sinTable_q31[indexS + 1];

	Dn = 0x1921FB5; /* delta between the two points (fixed), in this case 2*pi/FAST_MATH_TABLE_SIZE */
	Df = f2 - f1;   /* delta between the values of the functions */

	temp = Dn * ((q63_t)d1 + d2);
	temp = temp - ((q63_t)Df << 32);
	temp = (q63_t)fract * (temp >> 31);
	temp = temp + ((3 * (q63_t)Df << 31) - (d2 + ((q63_t)d1 << 1)) * Dn);
	temp = (q63_t)fract * (temp >> 31);
	temp = temp + (q63_t)d1 * Dn;
	temp = (q63_t)fract * (temp >> 31);

	/* Calculation of cosine value */
	*pCosVal = clip_q63_to_q31((temp >> 31) + (q63_t)f1);

	/* Read two nearest values of input value from the cos & sin tables */
	f1 = sinTable_q31[indexS ];
	f2 = sinTable_q31[indexS + 1];
	d1 = sinTable_q31[indexC ];
	d2 = sinTable_q31[indexC + 1];

	Df = f2 - f1; // delta between the values of the functions
	temp = Dn * ((q63_t)d1 + d2);
	temp = temp - ((q63_t)Df << 32);
	temp = (q63_t)fract * (temp >> 31);
	temp = temp + ((3 * (q63_t)Df << 31) - (d2 + ((q63_t)d1 << 1)) * Dn);
	temp = (q63_t)fract * (temp >> 31);
	temp = temp + (q63_t)d1 * Dn;
	temp = (q63_t)fract * (temp >> 31);

	/* Calculation of sine value */
	*pSinVal = clip_q63_to_q31((temp >> 31) + (q63_t)f1);
}

/**
  @} end of SinCos group
 */
